Browsing by Author "Kravchenko, Julia"
Now showing 1 - 17 of 17
Results Per Page
Sort Options
Item Open Access A Systematic Review of Conceptual Frameworks of Medical Complexity and New Model Development.(J Gen Intern Med, 2016-03) Zullig, Leah L; Whitson, Heather E; Hastings, Susan N; Beadles, Chris; Kravchenko, Julia; Akushevich, Igor; Maciejewski, Matthew LBACKGROUND: Patient complexity is often operationalized by counting multiple chronic conditions (MCC) without considering contextual factors that can affect patient risk for adverse outcomes. OBJECTIVE: Our objective was to develop a conceptual model of complexity addressing gaps identified in a review of published conceptual models. DATA SOURCES: We searched for English-language MEDLINE papers published between 1 January 2004 and 16 January 2014. Two reviewers independently evaluated abstracts and all authors contributed to the development of the conceptual model in an iterative process. RESULTS: From 1606 identified abstracts, six conceptual models were selected. One additional model was identified through reference review. Each model had strengths, but several constructs were not fully considered: 1) contextual factors; 2) dynamics of complexity; 3) patients' preferences; 4) acute health shocks; and 5) resilience. Our Cycle of Complexity model illustrates relationships between acute shocks and medical events, healthcare access and utilization, workload and capacity, and patient preferences in the context of interpersonal, organizational, and community factors. CONCLUSIONS/IMPLICATIONS: This model may inform studies on the etiology of and changes in complexity, the relationship between complexity and patient outcomes, and intervention development to improve modifiable elements of complex patients.Item Open Access Age patterns of incidence of geriatric disease in the U.S. elderly population: Medicare-based analysis.(J Am Geriatr Soc, 2012-02) Akushevich, Igor; Kravchenko, Julia; Ukraintseva, Svetlana; Arbeev, Konstantin; Yashin, Anatoliy IOBJECTIVES: To use the Medicare Files of Service Use (MFSU) to evaluate patterns in the incidence of aging-related diseases in the U.S. elderly population. DESIGN: Age-specific incidence rates of 19 aging-related diseases were evaluated using the National Long Term Care Survey (NLTCS) and the Surveillance, Epidemiology, and End Results (SEER) Registry data, both linked to MFSU (NLTCS-M and SEER-M, respectively), using an algorithm developed for individual date at onset evaluation. SETTING: A random sample from the entire U.S. elderly population (Medicare beneficiaries) was used in NLTCS, and the SEER Registry data covers 26% of the U.S. population. PARTICIPANTS: Thirty-four thousand seventy-seven individuals from NLTCS-M and 2,154,598 from SEER-M. MEASUREMENTS: Individual medical histories were reconstructed using information on diagnoses coded in MFSU, dates of medical services and procedures, and Medicare enrollment and disenrollment. RESULTS: The majority of diseases (e.g., prostate cancer, asthma, and diabetes mellitus) had a monotonic decline (or decline after a short period of increase) in incidence with age. A monotonic increase in incidence with age with a subsequent leveling off and decline was observed for myocardial infarction, stroke, heart failure, ulcer, and Alzheimer's disease. An inverted U-shaped age pattern was detected for lung and colon carcinomas, Parkinson's disease, and renal failure. The results obtained from the NLTCS-M and SEER-M were in agreement (excluding an excess for circulatory diseases in the NLTCS-M). A sensitivity analysis proved the stability of the incidence rates evaluated. CONCLUSION: The developed computational approaches applied to the nationally representative Medicare-based data sets allow reconstruction of age patterns of disease incidence in the U.S. elderly population at the national level with unprecedented statistical accuracy and stability with respect to systematic biases.Item Open Access Breast cancer as heterogeneous disease: contributing factors and carcinogenesis mechanisms.(Breast Cancer Res Treat, 2011-07) Kravchenko, Julia; Akushevich, Igor; Seewaldt, Victoria L; Abernethy, Amy P; Lyerly, H KimThe observed bimodal patterns of breast cancer incidence in the U.S. suggested that breast cancer may be viewed as more than one biological entity. We studied the factors potentially contributing to this phenomenon, specifically focusing on how disease heterogeneity could be linked to breast carcinogenesis mechanisms. Using empirical analyses and population-based biologically motivated modeling, age-specific patterns of incidence of ductal and lobular breast carcinomas from the SEER registry (1990-2003) were analyzed for heterogeneity and characteristics of carcinogenesis, stratified by race, stage, grade, and estrogen (ER)/progesterone (PR) receptor status. The heterogeneity of breast carcinoma age patterns decreased after stratification by grade, especially for grade I and III tumors. Stratification by ER/PR status further reduced the heterogeneity, especially for ER(+)/PR(-) and ER(-)/(-) tumors; however, the residual heterogeneity was still observed. The number of rate-limiting events of carcinogenesis and the latency of ductal and lobular carcinomas differed, decreasing from grade I to III, with poorly differentiated tumors associated with the least number of carcinogenesis stages and the shortest latency. Tumor grades play important role in bimodal incidence of breast carcinoma and have distinct mechanisms of carcinogenesis. Race and cancer subtype could play modifying role. ER/PR status contributes to the observed heterogeneity, but is subdominant to tumor grade. Further studies on sources of "remaining" heterogeneity of population with breast cancer (such as genetic/epigenetic characteristics) are necessary. The results of this study could suggest stratification rather than unification of breast cancer prevention strategies, risk assessment, and treatment.Item Open Access Cancer Risk and Behavioral Factors, Comorbidities, and Functional Status in the US Elderly Population.(ISRN Oncol, 2011) Akushevich, Igor; Kravchenko, Julia; Akushevich, Lucy; Ukraintseva, Svetlana; Arbeev, Konstantin; Yashin, AnatoliyAbout 80% of all cancers are diagnosed in the elderly and up to 75% of cancers are associated with behavioral factors. An approach to estimate the contribution of various measurable factors, including behavior/lifestyle, to cancer risk in the US elderly population is presented. The nationally representative National Long-Term Care Survey (NLTCS) data were used for measuring functional status and behavioral factors in the US elderly population (65+), and Medicare Claims files linked to each person from the NLTCS were used for estimating cancer incidence. The associations (i.e., relative risks) of selected factors with risks of breast, prostate, lung and colon cancers were evaluated and discussed. Behavioral risk factors significantly affected cancer risks in the US elderly. The most influential of potentially preventable risk factors can be detected with this approach using NLTCS-Medicare linked dataset and for further deeper analyses employing other datasets with detailed risk factors description.Item Open Access Cardiovascular comorbidities and survival of lung cancer patients: Medicare data based analysis.(Lung Cancer, 2017-06-05) Kravchenko, Julia; Berry, Mark; Arbeev, Konstantin; Lyerly, H Kim; Yashin, Anatoly; Akushevich, IgorOBJECTIVES: To evaluate the role of cardiovascular disease (CVD) comorbidity in survival of patients with non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: The impact of seven CVDs (at the time of NSCLC diagnosis and during subsequent follow-up) on overall survival was studied for NSCLC patients aged 65+ years using the Surveillance, Epidemiology, and End Results data linked to the U.S. Medicare data, cancer stage- and treatment-specific. Cox regression was applied to evaluate death hazard ratios of CVDs in univariable and multivariable analyses (controlling by age, TNM statuses, and 78 non-CVD comorbidities) and to investigate the effects of 128 different combinations of CVDs on patients' survival. RESULTS: Overall, 95,167 patients with stage I (n=29,836, 31.4%), II (n=5133, 5.4%), IIIA (n=11,884, 12.5%), IIIB (n=18,020, 18.9%), and IV (n=30,294, 31.8%) NSCLC were selected. Most CVDs increased the risk of death for stages I-IIIB patients, but did not significantly impact survival of stage IV patients. The worse survival of patients was associated with comorbid heart failure, myocardial infarction, and cardiac arrhythmias that occurred during a period of follow-up: HRs up to 1.85 (p<0.001), 1.96 (p<0.05), and 1.67 (p<0.001), respectively, varying by stage and treatment. The presence of hyperlipidemia at baseline (HR down to 0.71, p<0.05) was associated with better prognosis. Having multiple co-existing CVDs significantly increased mortality for all treatments, especially for stages I and II patients treated with surgery (HRs up to 2.89, p<0.05) and stages I-IIIB patients treated with chemotherapy (HRs up to 2.59, p<0.001) and chemotherapy and radiotherapy (HRs up to 2.20, p<0.001). CONCLUSION: CVDs impact the survival of NSCLC patients, particularly when multiple co-existing CVDs are present; the impacts vary by stage and treatment. This data should be considered in improving cancer treatment selection process for such potentially challenging patients as the elderly NSCLC patients with CVD comorbidities.Item Open Access Causal effects of time-dependent treatments in older patients with non-small cell lung cancer.(PLoS One, 2015) Akushevich, Igor; Arbeev, Konstantin; Kravchenko, Julia; Berry, MarkBACKGROUND: Treatment selection for elderly patients with lung cancer must balance the benefits of curative/life-prolonging therapy and the risks of increased mortality due to comorbidities. Lung cancer trials generally exclude patients with comorbidities and current treatment guidelines do not specifically consider comorbidities, so treatment decisions are usually made on subjective individual-case basis. METHODS: Impacts of surgery, radiation, and chemotherapy mono-treatment as well as combined chemo/radiation on one-year overall survival (compared to no-treatment) are studied for stage-specific lung cancer in 65+ y.o. patients. Methods of causal inference such as propensity score with inverse probability weighting (IPW) for time-independent and marginal structural model (MSM) for time-dependent treatments are applied to SEER-Medicare data considering the presence of comorbid diseases. RESULTS: 122,822 patients with stage I (26.8%), II (4.5%), IIIa (11.5%), IIIb (19.9%), and IV (37.4%) lung cancer were selected. Younger age, smaller tumor size, and fewer baseline comorbidities predict better survival. Impacts of radio- and chemotherapy increased and impact of surgery decreased with more advanced cancer stages. The effects of all therapies became weaker after adjustment for selection bias, however, the changes in the effects were minor likely due to the weak selection bias or incompleteness of the list of predictors that impacted treatment choice. MSM provides more realistic estimates of treatment effects than the IPW approach for time-independent treatment. CONCLUSIONS: Causal inference methods provide substantive results on treatment choice and survival of older lung cancer patients with realistic expectations of potential benefits of specific treatments. Applications of these models to specific subsets of patients can aid in the development of practical guidelines that help optimize lung cancer treatment based on individual patient characteristics.Item Open Access Circulatory Diseases in the U.S. Elderly in the Linked National Long-Term Care Survey-Medicare Database: Population-Based Analysis of Incidence, Comorbidity, and Disability.(Res Aging, 2013-07) Akushevich, Igor; Kravchenko, Julia; Ukraintseva, Svetlana; Arbeev, Konstantin; Yashin, Anatoli IIncidence rates of acute coronary heart disease (ACHD; including myocardial infarction and angina pectoris), stroke, and heart failure (HF) were studied for their age, disability, and comorbidity patterns in the U.S. elderly population using the National Long Term Care Survey (NLTCS) data linked to Medicare records for 1991-2005. Incidence rates increased with age with a decrease in the oldest old (stroke and HF) or were stable at all ages (ACHD). For all diseases, incidence rates were lower among institutionalized individuals and higher in individuals with higher comorbidity indices. The results could be used for understanding currently debated effects of biomedical research, screening, and therapeutic innovations on changes in disease incidence with advancing age as well as for projecting future Medicare costs.Item Open Access Epidemiology of geographic disparities in heart failure among US older adults: a Medicare-based analysis.(BMC public health, 2022-07) Yu, Bin; Akushevich, Igor; Yashkin, Arseniy P; Yashin, Anatoliy I; Lyerly, H Kim; Kravchenko, JuliaBackground
There are prominent geographic disparities in the life expectancy (LE) of older US adults between the states with the highest (leading states) and lowest (lagging states) LE and their causes remain poorly understood. Heart failure (HF) has been proposed as a major contributor to these disparities. This study aims to investigate geographic disparities in HF outcomes between the leading and lagging states.Methods
The study was a secondary data analysis of HF outcomes in older US adults aged 65+, using Center for Disease Control and Prevention sponsored Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) database and a nationally representative 5% sample of Medicare beneficiaries over 2000-2017. Empiric estimates of death certificate-based mortality from HF as underlying cause of death (CBM-UCD)/multiple cause of death (CBM-MCD); HF incidence-based mortality (IBM); HF incidence, prevalence, and survival were compared between the leading and lagging states. Cox regression was used to investigate the effect of residence in the lagging states on HF incidence and survival.Results
Between 2000 and 2017, HF mortality rates (per 100,000) were higher in the lagging states (CBM-UCD: 188.5-248.6; CBM-MCD: 749.4-965.9; IBM: 2656.0-2978.4) than that in the leading states (CBM-UCD: 79.4-95.6; CBM-MCD: 441.4-574.1; IBM: 1839.5-2138.1). Compared to their leading counterparts, lagging states had higher HF incidence (2.9-3.9% vs. 2.2-2.9%), prevalence (15.6-17.2% vs. 11.3-13.0%), and pre-existing prevalence at age 65 (5.3-7.3% vs. 2.8-4.1%). The most recent rates of one- (77.1% vs. 80.4%), three- (59.0% vs. 60.7%) and five-year (45.8% vs. 49.8%) survival were lower in the lagging states. A greater risk of HF incidence (Adjusted Hazards Ratio, AHR [95%CI]: 1.29 [1.29-1.30]) and death after HF diagnosis (AHR: 1.12 [1.11-1.13]) was observed for populations in the lagging states. The study also observed recent increases in CBMs and HF incidence, and declines in HF prevalence, prevalence at age 65 and survival with a decade-long plateau stage in IBM in both leading and lagging states.Conclusion
There are substantial geographic disparities in HF mortality, incidence, prevalence, and survival across the U.S.: HF incidence, prevalence at age 65 (age of Medicare enrollment), and survival of patients with HF contributed most to these disparities. The geographic disparities and the recent increase in incidence and decline in survival underscore the importance of HF prevention strategies.Item Open Access Evaluating the number of stages in development of squamous cell and adenocarcinomas across cancer sites using human population-based cancer modeling.(PLoS One, 2012) Kravchenko, Julia; Akushevich, Igor; Abernethy, Amy P; Lyerly, H KimBACKGROUND: Adenocarcinomas (ACs) and squamous cell carcinomas (SCCs) differ by clinical and molecular characteristics. We evaluated the characteristics of carcinogenesis by modeling the age patterns of incidence rates of ACs and SCCs of various organs to test whether these characteristics differed between cancer subtypes. METHODOLOGY/PRINCIPAL FINDINGS: Histotype-specific incidence rates of 14 ACs and 12 SCCs from the SEER Registry (1973-2003) were analyzed by fitting several biologically motivated models to observed age patterns. A frailty model with the Weibull baseline was applied to each age pattern to provide the best fit for the majority of cancers. For each cancer, model parameters describing the underlying mechanisms of carcinogenesis including the number of stages occurring during an individual's life and leading to cancer (m-stages) were estimated. For sensitivity analysis, the age-period-cohort model was incorporated into the carcinogenesis model to test the stability of the estimates. For the majority of studied cancers, the numbers of m-stages were similar within each group (i.e., AC and SCC). When cancers of the same organs were compared (i.e., lung, esophagus, and cervix uteri), the number of m-stages were more strongly associated with the AC/SCC subtype than with the organ: 9.79±0.09, 9.93±0.19 and 8.80±0.10 for lung, esophagus, and cervical ACs, compared to 11.41±0.10, 12.86±0.34 and 12.01±0.51 for SCCs of the respective organs (p<0.05 between subtypes). Most SCCs had more than ten m-stages while ACs had fewer than ten m-stages. The sensitivity analyses of the model parameters demonstrated the stability of the obtained estimates. CONCLUSIONS/SIGNIFICANCE: A model containing parameters capable of representing the number of stages of cancer development occurring during individual's life was applied to the large population data on incidence of ACs and SCCs. The model revealed that the number of m-stages differed by cancer subtype being more strongly associated with ACs/SCCs histotype than with organ/site.Item Open Access Medical cost trajectories and onsets of cancer and noncancer diseases in US elderly population.(Comput Math Methods Med, 2011) Akushevich, Igor; Kravchenko, Julia; Akushevich, Lucy; Ukraintseva, Svetlana; Arbeev, Konstantin; Yashin, Anatoliy ITime trajectories of medical costs-associated with onset of twelve aging-related cancer and chronic noncancer diseases were analyzed using the National Long-Term Care Survey data linked to Medicare Service Use files. A special procedure for selecting individuals with onset of each disease was developed and used for identification of the date at disease onset. Medical cost trajectories were found to be represented by a parametric model with four easily interpretable parameters reflecting: (i) prediagnosis cost (associated with initial comorbidity), (ii) cost of the disease onset, (iii) population recovery representing reduction of the medical expenses associated with a disease since diagnosis was made, and (iv) acquired comorbidity representing the difference between post- and pre diagnosis medical cost levels. These parameters were evaluated for the entire US population as well as for the subpopulation conditional on age, disability and comorbidity states, and survival (2.5 years after the date of onset). The developed approach results in a family of new forecasting models with covariates.Item Open Access Morbidity risks among older adults with pre-existing age-related diseases.(Exp Gerontol, 2013-12) Akushevich, Igor; Kravchenko, Julia; Ukraintseva, Svetlana; Arbeev, Konstantin; Kulminski, Alexander; Yashin, Anatoliy IMulti-morbidity is common among older adults; however, for many aging-related diseases there is no information for U.S. elderly population on how earlier-manifested disease affects the risk of another disease manifested later during patient's lifetime. Quantitative evaluation of risks of cancer and non-cancer diseases for older adults with pre-existing conditions is performed using the Surveillance, Epidemiology, and End Results (SEER) Registry data linked to the Medicare Files of Service Use (MFSU). Using the SEER-Medicare data containing individual records for 2,154,598 individuals, we empirically evaluated age patterns of incidence of age-associated diseases diagnosed after the onset of earlier manifested disease and compared these patterns with those in general population. Individual medical histories were reconstructed using information on diagnoses coded in MFSU, dates of medical services/procedures, and Medicare enrollment/disenrollment. More than threefold increase of subsequent diseases risk was observed for 15 disease pairs, majority of them were i) diseases of the same organ and/or system (e.g., Parkinson disease for patients with Alzheimer disease, HR=3.77, kidney cancer for patients with renal failure, HR=3.28) or ii) disease pairs with primary diseases being fast-progressive cancers (i.e., lung, kidney, and pancreas), e.g., ulcer (HR=4.68) and melanoma (HR=4.15) for patients with pancreatic cancer. Lower risk of subsequent disease was registered for 20 disease pairs, mostly among patients with Alzheimer's or Parkinson's disease, e.g., decreased lung cancer risk among patients with Alzheimer's (HR=0.64) and Parkinson's (HR=0.60) disease. Synergistic and antagonistic dependences in geriatric disease risks were observed among US elderly confirming known and detecting new associations of wide spectrum of age-associated diseases. The results can be used in optimization of screening, prevention and treatment strategies of chronic diseases among U.S. elderly population.Item Open Access New stochastic carcinogenesis model with covariates: an approach involving intracellular barrier mechanisms.(Math Biosci, 2012-03) Akushevich, Igor; Veremeyeva, Galina; Kravchenko, Julia; Ukraintseva, Svetlana; Arbeev, Konstantin; Akleyev, Alexander V; Yashin, Anatoly IIn this paper we present a new multiple-pathway stochastic model of carcinogenesis with potential of predicting individual incidence risks on the basis of biomedical measurements. The model incorporates the concept of intracellular barrier mechanisms in which cell malignization occurs due to an inefficient operation of barrier cell mechanisms, such as antioxidant defense, repair systems, and apoptosis. Mathematical formalism combines methodological innovations of mechanistic carcinogenesis models and stochastic process models widely used in studying biodemography of aging and longevity. An advantage of the modeling approach is in the natural combining of two types of measures expressed in terms of model parameters: age-specific hazard rate and means of barrier states. Results of simulation studies allow us to conclude that the model parameters can be estimated in joint analyses of epidemiological data and newly collected data on individual biomolecular measurements of barrier states. Respective experimental designs for such measurements are suggested and discussed. An analytical solution is obtained for the simplest design when only age-specific incidence rates are observed. Detailed comparison with TSCE model reveals advantages of the approach such as the possibility to describe decline in risk at advanced ages, possibilities to describe heterogeneous system of intermediate cells, and perspectives for individual prognoses of cancer risks. Application of the results to fit the SEER data on cancer risks demonstrates a strong predictive power of the model. Further generalizations of the model, opportunities to measure barrier systems, biomedical and mathematical aspects of the new model are discussed.Item Open Access Recovery and survival from aging-associated diseases.(Exp Gerontol, 2013-08) Akushevich, Igor; Kravchenko, Julia; Ukraintseva, Svetlana; Arbeev, Konstantin; Yashin, Anatoliy IOBJECTIVES: Considering disease incidence to be a main contributor to healthy lifespan of the US elderly population may lead to erroneous conclusions when recovery/long-term remission factors are underestimated. Using two Medicare-based population datasets, we investigated the properties of recovery from eleven age-related diseases. METHODS: Cohorts of patients who stopped visiting doctors during a five-year follow-up since disease onset were analyzed non-parametrically and using the Cox proportional hazard model resulted in estimated recovery and survival rates and evaluated the health state of recovered individuals by comparing their survival with non-recovered patients and the general population. RESULTS: Recovered individuals had lower death rates than non-recovered patients, therefore, patients who stopped visiting doctors are a healthier subcohort. However, they had higher death rates than in general population for all considered diseases, therefore the complete recovery does not occur. CONCLUSION: Properties of recovery/long-term remission among the US population of older adults with chronic diseases were uncovered and evaluated. The results allow for a better quantifiable contribution of age-related diseases to healthy life expectancy and improving forecasts of health and mortality.Item Open Access The effect of non-fluoride factors on risk of dental fluorosis: Evidence from rural populations of the Main Ethiopian Rift(Science of the Total Environment, 2014-08-01) Kravchenko, Julia; Rango, Tewodros; Akushevich, Igor; Atlaw, Behailu; McCornick, Peter G; Merola, R Brittany; Paul, Christopher; Weinthal, Erika; Harrison, Courtney; Vengosh, Avner; Jeuland, MarcElevated level of fluoride (F-) in drinking water is a well-recognized risk factor of dental fluorosis (DF). While considering optimization of region-specific standards for F-, it is reasonable, however, to consider how local diet, water sourcing practices, and non-F- elements in water may be related to health outcomes. In this study, we hypothesized that non-F- elements in groundwater and lifestyle and demographic characteristics may be independent predictors or modifiers of the effects of F- on teeth. Dental examinations were conducted among 1094 inhabitants from 399 randomly-selected households of 20 rural communities of the Ziway-Shala lake basin of the Main Ethiopian Rift. DF severity was evaluated using the Thylstrup-Fejerskov Index (TFI). Household surveys were performed and water samples were collected from community water sources. To consider interrelations between the teeth within individual (in terms of DF severity) and between F- and non-F- elements in groundwater, the statistical methods of regression analysis, mixed models, and principal component analysis were used.About 90% of study participants consumed water from wells with F- levels above the WHO recommended standard of 1.5mg/l. More than 62% of the study population had DF. F- levels were a major factor associated with DF. Age, sex, and milk consumption (both cow's and breastfed) were also statistically significantly (p<0.05) associated with DF severity; these associations appear both independently and as modifiers of those identified between F- concentration and DF severity. Among 35 examined elements in groundwater, Ca, Al, Cu, and Rb were found to be significantly correlated with dental health outcomes among the residents exposed to water with excessive F- concentrations.Quantitative estimates obtained in our study can be used to explore new water treatment strategies, water safety and quality regulations, and lifestyle recommendations which may be more appropriate for this highly populated region. © 2013 Elsevier B.V.Item Open Access Time trends of incidence of age-associated diseases in the US elderly population: Medicare-based analysis.(Age Ageing, 2013-07) Akushevich, Igor; Kravchenko, Julia; Ukraintseva, Svetlana; Arbeev, Konstantin; Yashin, Anatoly IOBJECTIVES: time trends of age-adjusted incidence rates of 19 ageing-related diseases were evaluated for 1992-2005 period with the National Long Term Care Survey and the Surveillance, Epidemiology and End RESULTS Registry data both linked to Medicare data (NLTCS-Medicare and SEER-Medicare, respectively). METHODS: the rates were calculated using individual medical histories (34,077 individuals from NLTCS-Medicare and 199,418 from SEER-Medicare) reconstructed using information on diagnoses coded in Medicare data, dates of medical services/procedures and Medicare enrolment/disenrolment. RESULTS: increases of incidence rates were dramatic for renal disease [the average annual percent change (APC) is 8.56%, 95% CI = 7.62, 9.50%], goiter (APC = 6.67%, 95% CI = 5, 90, 7, 44%), melanoma (APC = 6.15%, 95% CI = 4.31, 8.02%) and Alzheimer's disease (APC = 3.96%, 95% CI = 2.67, 5.26%), and less prominent for diabetes and lung cancer. Decreases of incidence rates were remarkable for angina pectoris (APC = -6.17%, 95% CI = -6.96, -5.38%); chronic obstructive pulmonary disease (APC = -5.14%, 95% CI = -6.78,-3.47%), and ulcer (APC = -5.82%, 95% CI = -6.77,-4.86%) and less dramatic for carcinomas of colon and prostate, stroke, hip fracture and asthma. Incidence rates of female breast carcinoma, myocardial infarction, Parkinson's disease and rheumatoid arthritis were almost stable. For most diseases, an excellent agreement was observed for incidence rates between NLTCS-Medicare and SEER-Medicare. A sensitivity analysis proved the stability of the evaluated time trends. CONCLUSION: time trends of the incidence of diseases common in the US elderly population were evaluated. The results show dramatic increase in incidence rates of melanoma, goiter, chronic renal and Alzheimer's disease in 1992-2005. Besides specifying widely recognised time trends on age-associated diseases, new information was obtained for trends of asthma, ulcer and goiter among the older adults in the USA.Item Open Access Transitional probability-based model for HPV clearance in HIV-1-positive adolescent females.(PLoS One, 2012) Kravchenko, Julia; Akushevich, Igor; Sudenga, Staci L; Wilson, Craig M; Levitan, Emily B; Shrestha, SadeepBACKGROUND: HIV-1-positive patients clear the human papillomavirus (HPV) infection less frequently than HIV-1-negative. Datasets for estimating HPV clearance probability often have irregular measurements of HPV status and risk factors. A new transitional probability-based model for estimation of probability of HPV clearance was developed to fully incorporate information on HIV-1-related clinical data, such as CD4 counts, HIV-1 viral load (VL), highly active antiretroviral therapy (HAART), and risk factors (measured quarterly), and HPV infection status (measured at 6-month intervals). METHODOLOGY AND FINDINGS: Data from 266 HIV-1-positive and 134 at-risk HIV-1-negative adolescent females from the Reaching for Excellence in Adolescent Care and Health (REACH) cohort were used in this study. First, the associations were evaluated using the Cox proportional hazard model, and the variables that demonstrated significant effects on HPV clearance were included in transitional probability models. The new model established the efficacy of CD4 cell counts as a main clearance predictor for all type-specific HPV phylogenetic groups. The 3-month probability of HPV clearance in HIV-1-infected patients significantly increased with increasing CD4 counts for HPV16/16-like (p<0.001), HPV18/18-like (p<0.001), HPV56/56-like (p = 0.05), and low-risk HPV (p<0.001) phylogenetic groups, with the lowest probability found for HPV16/16-like infections (21.60±1.81% at CD4 level 200 cells/mm(3), p<0.05; and 28.03±1.47% at CD4 level 500 cells/mm(3)). HIV-1 VL was a significant predictor for clearance of low-risk HPV infections (p<0.05). HAART (with protease inhibitor) was significant predictor of probability of HPV16 clearance (p<0.05). HPV16/16-like and HPV18/18-like groups showed heterogeneity (p<0.05) in terms of how CD4 counts, HIV VL, and HAART affected probability of clearance of each HPV infection. CONCLUSIONS: This new model predicts the 3-month probability of HPV infection clearance based on CD4 cell counts and other HIV-1-related clinical measurements.Item Open Access Vulnerability to Hypertension Is a Major Determinant of Racial Disparities in Alzheimer's Disease Risk.(American journal of hypertension, 2022-08) Akushevich, Igor; Kolpakov, Stanislav; Yashkin, Arseniy P; Kravchenko, JuliaBackground
Higher incidence levels of Alzheimer's disease (AD) in Black Americans are well documented. However, quantitative explanations of this disparity in terms of risk-factor diseases acting through well-defined pathways are lacking.Methods
We applied a Blinder-Oaxaca-based algorithm modified for censored data to a 5% random sample of Medicare beneficiaries age 65+ to explain Black/White disparities in AD risk in terms of differences in exposure and vulnerability to morbidity profiles based on 10 major AD-risk-related diseases.Results
The primary contribution to racial disparities in AD risk comes from morbidity profiles that included hypertension with about 1/5th of their contribution due to differences in prevalence (exposure effect) and 4/5ths to differences in the effects of the morbidity profile on AD risk (vulnerability effect). In total, disease-related effects explained a higher proportion of AD incidence in Black Americans than in their White counterparts.Conclusions
Disease-related causes may represent some of the most straightforward targets for targeted interventions aimed at the reduction of racial disparities in health among US older adults. Hypertension is a manageable and potentially preventable condition responsible for the majority of the Black/White differences in AD risk, making mitigation of the role of this disease in engendering higher AD incidence in Black Americans a prominent concern.